About Greenplum Database Master and Local Parameters

The master and each segment instance have their own postgresql.conf
file. Some parameters are local: each segment instance examines its
postgresql.conf file to get the value of that parameter. Set local
parameters on the master and on each segment instance.

Other parameters are master parameters that you set on the master instance. The value
is passed down to (or in some cases ignored by) the segment instances at query run time.

See the Greenplum Database Reference Guide for information
about local and master server configuration parameters.